The goal of this project is to develop a more comprehensive understanding of the role and significance of stereochemistry within the metabolism of cyclophosphamide, as related to the selective toxicity of this anticancer drug. Currently available data indicate the therapeutic benefits of enantiomerically pure cyclophosphamide; we believe that an increased knowledge of the stereochemical discrimination factors applicable to cyclophosphamide can be utilized to obtain further improvements that may be extended to the better treatment of human cancers. The stereochemical behavior of cyclophosphamide and cyclophosphamide metabolites is being probed primarily by high resolution 1H, 13C, and 31P nuclear magnetic resonance spectroscopy. BIBLIOGRAPHIC REFERENCES: Zon, G., Brandt, J.A., and Egan, W. Determination of Enantiomeric Homogeneity (Optical Purity) of Cyclophosphamide by Nuclear Magnetic Resonance Spectroscopy. J. Nat'l. Cancer Inst., 58, 1977. Karle, I.L., Karle, J.M., Egan, W., Zon, G. and Brandt, J.A.: The Absolute Configuration of (+) - Cyclophosphamide: A Crystal and Molecular Structure Determination., J. Amer. Chem. Soc. 99, 1977.